View Full Version : Studies showing piston Ar's more reliable?
Complete ignorance here- are there any?
I just don't understand the fascination with a more complex, heavier system of operation. Especially since there are about 10 different versions- which get discontinued etc....Good luck find parts for that in 10 years. It's never made any sense to me. DI works very well. The only reason I could think of to do anything else would be some real evidence that somehow piston guns are more reliable, but I'm not aware of any real studies that show that.
DI in a quality gun has always been a proven design. I don’t understand the fascination with piston driven ARs either. I get what they are trying to say about less blowback into the action but a quality DI gun that’s well maintained (as any serious defensive gun should be) is the way to go in my humble opinion.
Sent from my iPhone using Tapatalk
I wanna say there was a study done around the time of the SCAR program that includes the HK416. So I think there is info regarding it. However that's more just a study of the 416 vs the M16/M4 and not a piston vs DI thing.
I wanna say there was a study done around the time of the SCAR program that includes the HK416. So I think there is info regarding it. However that's more just a study of the 416 vs the M16/M4 and not a piston vs DI thing.
I’ve always just owned DI guns, shot them a ton but never in any harsh environments if you will. I could see the argument for something that be able to run through dirty/harsh environments on an autoloading firearm. The classic scenario I think of when I hear about complaints about DI guns not running when in dirty/harsh environments is the M4 out in the sandbox but I don’t know how well some of those rifles were maintained either but then again I was never there so that’s just a thought. One thing I’m curious about on a piston driven platform since I’ve never owned a piston driven AR is how much carbon buildup actually builds up in the piston and how often that has to be cleaned/maintained?
Sent from my iPad using Tapatalk
pointblank4445
10-01-21, 11:07
I wanna say there was a study done around the time of the SCAR program that includes the HK416. So I think there is info regarding it. However that's more just a study of the 416 vs the M16/M4 and not a piston vs DI thing.
Probably thinking about the "dust tests"
https://www.military.com/defensetech/2007/12/17/m4-comes-in-last-place-in-dust-test
I think the only AR-pattern op rod that has a case for it is the 416 and most of that context is in relationship to the 10.4" DI variants of the day. And as some may remember, the HK was not without some teething/production issues and has enjoyed several production improvements along the way.
In the context of today's knowledge, it has been surmised by industry types that perhaps a significant portion of the HK's success may not be due to the op rod but just in the use of different materials, alloys and their otherwise German approach to the AR platform...
I think one is hard-pressed to find a simple cut-and-dry answer given that context and cost are always going to be a factor. I do believe that in certain roles, configurations and environments, there are advantages to the 416 op rod IF one insists on having an AR pattern gun.
I don't know of any studies (maybe one related to the HK piston AR's??), but I remember reading in some gun rags of the late 70's and 80's how the heavier and cleaner BCG of the AK made them SO much more reliable than the unreliable and whispy M16. So the idea of converting AR's to pistons I believe started there. The total piece of junk "RHINO" system of the day was the first attempt at a piston conversion that I'm aware of. I guess some people through the decades just couldn't let the idea go.
If you run suppressed there is definitely a case to be made that they run cleaner than a DI gun. Also less gas to the face. I wanted a PWS in the worst way until I picked one up and the added weight was noticeable. It's hard to argue with the design. A couple billion AKs are still out there running strong.
pointblank4445
10-01-21, 11:51
I don't know of any studies (maybe one related to the HK piston AR's??), but I remember reading in some gun rags of the late 70's and 80's how the heavier and cleaner BCG of the AK made them SO much more reliable than the unreliable and whispy M16. So the idea of converting AR's to pistons I believe started there. The total piece of junk "RHINO" system of the day was the first attempt at a piston conversion that I'm aware of. I guess some people through the decades just couldn't let the idea go.
Certainly, there was no bias or propaganda from them days...no sir. It was well into the 90's and 2000's that most folks still believed the AR pattern was crap and would seize up at the drop of a hat and the AK was an indestructible force of nature that an untrained chimp could operate in the harshest climates that would kill mortal man.
Long before the days of the reality: "The AR is more reliable that it gets credit for, and the AK is more accurate than it gets credit for".
All that being said, I'm not so sure the AR18 pattern stuff isn't going to be the best vehicle for a small-frame semi-auto carbine once it gets its due development time (if that ever happens given the state of things)
The largest problem is that reports are often setup to reveal the info the researcher wants. You want DI to win, ok, easy. You want piston to win? Ok, easy.
If you want to see ugly back door politics and money at play, dig into weapon testing and / or supplying military arms.
If you want to see ugly back door politics and money at play, dig into weapon testing and / or supplying military arms.
https://en.wikipedia.org/wiki/The_Pentagon_Wars
I still like Piston for suppression and full auto fire, other than that, I don't see a point.
The largest problem is that reports are often setup to reveal the info the researcher wants. You want DI to win, ok, easy. You want piston to win? Ok, easy.
Outcome driven research. I think the bigger issue is that people consume reports like these and regurgitate them as being gospel. No critical thinking ability. I blame the interwebs.
I have a single piston AR, a 16" PWS Mod 2 which weighs 6.5 lbs, right in line with my other 16" DI rifles. The long stroke piston design gives it the same number of moving parts as DI, and it does have the benefit of less gas and sound to the shooter when shooting suppressed. Actually very pleased with it, and thinking of picking up one of their 11.9" uppers for a suppressed pistol build.
I can't really speak to overall reliability as I haven't any issues with any of my rifles, thankfully.
I'd trust a study showing reliability on a piston AR about as much as I trust the CDC or World Health Organization. :stop:
(Wait! Dr Fauci has a piston study coming out!)
Deadman William
10-01-21, 17:01
piston ARs are either novelty or special use. i dont really think of them as ARs, myself, and dont compare them to DI rifles in my own mind - they arent ARs. theyre heavily modified ARs. and since i like the DI design, dont shoot suppressed, i have no use for them.
as to which is more reliable.... boy i just dont think thats a question worth asking. there are far, far, far too many variables - too many if/then questions/answers to ask and answer before we can make anything close to a strong apples-to-oranges comparison and say with any degree of certainty that any particular family of piston designs is or isnt more reliable than DI.
if you would benefit from a piston AR, you already know it and can make that call, methinx. for everyone else, DI is the starting point.
There is an excellent discussion of the reliability of the HK416 in P&S Modcast 100 on YouTube. https://www.youtube.com/watch?v=pyYODtiohzQ&t=3849s Around the 50 minute or so mark, Chuck Pressburg goes into discussion of the 9 years he was deployed in Irag and/or Afghanistan as a member of an elite special forces group. Had virtually no malfunctions and never cleaned his weapon during the entire time he was deployed. He is a big HK416 fan, as you can imagine. Not a test but a real life experience with the HK416. Personally, I own a bunch of piston rifles (HK416/556, Sig 516, Sig MCX Virtus) and also several DI rifles (Centurion Arms all). They all shoot well, but if I had to choose, I'm taking the 416/556 every day of the week.
In the context of today's knowledge, it has been surmised by industry types that perhaps a significant portion of the HK's success may not be due to the op rod but just in the use of different materials, alloys and their otherwise German approach to the AR platform...
HK put the infomercial out of a 416 vs. an M4 and one of the demos was pulling both out of water and firing immediately that resulted in the Colt barrel bursting while the 416. If I recall right, it was at least implied that the difference was the piston, but the 416 barrel is cold hammer forged(which I have read a few places are more burst resistant than traditional barrels).
Anyone seen any testing as to piston giving that result versus barrel manufacturing process?
HK put the infomercial out of a 416 vs. an M4 and one of the demos was pulling both out of water and firing immediately that resulted in the Colt barrel bursting while the 416. If I recall right, it was at least implied that the difference was the piston, but the 416 barrel is cold hammer forged(which I have read a few places are more burst resistant than traditional barrels).
Anyone seen any testing as to piston giving that result versus barrel manufacturing process?
That is a feature with the HK that has support inside the chamber called OTB (over the beach). The Sig 516 (designed by the same engineer that was responsible for the HK 416) has the same feature. There is no doubt that the 416, and to some degree, the 516, are grossly over engineered compared to a normal M4
HK put the infomercial out of a 416 vs. an M4 and one of the demos was pulling both out of water and firing immediately that resulted in the Colt barrel bursting while the 416. If I recall right, it was at least implied that the difference was the piston, but the 416 barrel is cold hammer forged(which I have read a few places are more burst resistant than traditional barrels).
Anyone seen any testing as to piston giving that result versus barrel manufacturing process?
That is a feature with the HK that has support inside the chamber called OTB (over the beach). The Sig 516 (designed by the same engineer that was responsible for the HK 416) has the same feature. There is no doubt that the 416, and to some degree, the 516, are grossly over engineered compared to a normal M4
As I recall, Colt sued over that demo and showed that while the HK was pointed down to drain and given about a second longer to do so, the M4's barrel was slightly pointed up and fired without any such delay.
Honestly I don't get what the big deal is. Assuming neither version is slapped together from airsoft parts get whichever, both work fine
Sent from my moto z4 using Tapatalk
Yep both do work fine.
I own HK piston rifles and they are excellent. I also own DI AR’s and they are also excellent.
The biggest advantage to my HK piston rifles is how easy they are to clean.
You don’t get any carbon fouling beyond the tappet piston. The bolt stays pristine, which isn’t the case with my DI rifles.
I have 2 Sig Sauer 516 uppers and a Colt 6920 SOCOM that have run flawlessly for years.
When I first got the Sig I was worried about parts, but there really isn't anything that will break. The piston is heavy duty, the bolt and firing pin is the same as a DI AR and the only thing different is the BCG doesn't have the gas key, just a solid blank.
The only issue I've had with a DI gun is a cheaper upper that didn't have a pinned gas block that moved.
Either way an AR from a quality manufacturer whether or not if it's piston or DI should last for years without issues.
Sent from my SM-N986U using Tapatalk
Not a study, but straight from the mouth of Karl Lewis when asked what advantage his piston guns had over his DI guns.
"Well, the pistons are more expensive to build. I make a little more profit on them."
So there's that.
I’ve always just owned DI guns, shot them a ton but never in any harsh environments if you will. I could see the argument for something that be able to run through dirty/harsh environments on an autoloading firearm. The classic scenario I think of when I hear about complaints about DI guns not running when in dirty/harsh environments is the M4 out in the sandbox but I don’t know how well some of those rifles were maintained either but then again I was never there so that’s just a thought. One thing I’m curious about on a piston driven platform since I’ve never owned a piston driven AR is how much carbon buildup actually builds up in the piston and how often that has to be cleaned/maintained?
Sent from my iPad using Tapatalk
Iraq (and I assume Afghanistan as well) were definitely some harsh environments on the guns. But it's not like they were hard to clean. I spent literally a few minutes each week to wipe of the BCG and inside the upper and re-lube. The main problem was a myth, that was Army wide, that CLP attracted dirt and made the gun dirtier. So some guys would run their rifles dry, which is stupid. Keep your dust cover closed, the barrel cap on, and dont strap your rifle to the outside of the truck and the rifle stays pretty clean on the inside. Weapons maintenance in a warzone is important. I can tell you Ive seen plenty of AK47s malfunction because the Iraqi Army had piss poor weapons maintenance.
I think piston ARs can be very good guns if they are designed from the ground up as piston guns. The 416 and the PWS rifles are actually redesigned to make them piston guns. The rifles that just retrofit a piston system on a standard AR15 are usually junk in my experience/opinion.
turnburglar
10-02-21, 16:08
One of my buddies was a T1 type and spent a couple years in iraq with the 416. He said the same thing other's have said; I rarely cleaned it and it ran like a champ every single time. Keep in mind he was using the 10" with a suppressor.
I think a lot of people need to keep in mind when certain things like the 416 came around; what the development was on the current AR platform. It's pretty well documented that the 'shorty AR' wasn't a reliable animal until crane got involved. The US military hasn't ALWAYS had MK18's with DD rails in the inventory. That was an evolutionary thing that took awhile to happen. I think it is absolutely valid to question and weigh each system against one another, it's just important to keep it apples to apples. For example take the modern 416A5 and run that against a DD in similar barrel lengths doing similar tests.
I have always heard that the piston AR shines when you need a gun to do 3 things: Short barrel, suppressed, full auto. Once you stray outside of that very small niche a DI always makes more sense. I dont shoot suppressed but I have tens of thousands of trouble free rounds out of my DI guns at this point. So piston doesn't really do anything I already get done.
https://en.wikipedia.org/wiki/The_Pentagon_Wars
I still like Piston for suppression and full auto fire, other than that, I don't see a point.
[Devil's Advocate here] One could make the argument, based on what you said, that suppressed and FA are more "extreme" firing conditions. Therefore why wouldn't you want a system that operated under those more "extreme" conditions? Under near-perfect conditions it should run forever then.
Having made that point, and like it or not, I do believe that DI is not the wave of future small arms design. Adding a piston to an AR is back-engineering and usually doesn't work out. However, designing a piston driven weapon from the ground up is where it's going to be at.
I don't know for sure, but the DI system ran fine for me, in the Marines. My first rifle was the A1, then we went to the A2....would shoot a lot of rounds through them, and other than a quick spray of CLP, we could run quite a few rounds before it would get really sluggish or malfunction.
I have zero experience with a piston driven AR, so I cannot chime in on that side of the discussion, but I was at the range this morning, and my AR ran just fine for a couple hundred rounds. Other than "eating where it poops", I have complete confidence in the DI system. JMHO
I don't know for sure, but the DI system ran fine for me, in the Marines. My first rifle was the A1, then we went to the A2....would shoot a lot of rounds through them, and other than a quick spray of CLP, we could run quite a few rounds before it would get really sluggish or malfunction.
I have zero experience with a piston driven AR, so I cannot chime in on that side of the discussion, but I was at the range this morning, and my AR ran just fine for a couple hundred rounds. Other than "eating where it poops", I have complete confidence in the DI system. JMHO
Oh for sure it's pretty damn reliable if properly maintained. It is generally lighter too. I just don't see it as the "wave of the future" in small arms design.
LOL on the M16A1. You're an "old" bastage like me! Had an A1 for my entire 4 years as an Army grunt (see sigline). Of course the 20" rifle-length gas system is the one which the entire weapon was originally designed around, and that pencil-profile A1 barrel made it no heavier than some modern M4A1's. Then you add on the doo-dads commonly carried nowadays and the beauty of the A1 becomes more clear! My A1 clone that I have for old time's sake has a 1:7 twist barrel so I can shoot the better modern ammo.
In a shot (7-9 inch) barrel pistol, piston AR's seem more reliable. I prefer DI over Piston, that being said, more AR platforms are a good thing to help improve & innovate all AR systems, DI & Piston.
I have both systems and while I stick with the pistons being suppressed and short barreled… I have exceptions with both sides.
Piston system was my first AR. Spikes upper with AA kit… installed by Spikes. Had a great 1:8” barrel, but had an issue with the barrel spinning in the extension… Spikes was zero help, but barrel was AA’s, who warrantied it with a 1:7” barrel (AA is good people to do it). Was NJ compliant when I got it, but now is set up for my suppressor that is sitting in jail. It is a heavy setup, but I don’t see any issues other than that.
My truck gun is a 11.5” AA upper, which I got since I figured I was going to suppress it. Had a bad piston rod, which AA replaced (bad heat treatment, looked like it had Peyronie’s Disease inside the upper).
For D/I… my first was a .45 ACP upper from Macon Armory. Really nice setup, especially compared to blowback (I do have a 9mm blowback pistol, and a .22 upper). Eventually want to SBR that. It is cute with the 1.5” gas tube.
After that, I built a PSA pistol as a homage to Heat (11.5” Colt 733). Has a binary trigger, mainly for s***s/giggles and the third position. No issues with that, either the rate of fire or 11.5” barrel. I don’t have shorter than 11.5”… but if I did, I’d likely go piston.
I have another binary lower, which I haven’t got an upper for. Planning on a 20” A4 upper, as I wanted a longer barrel AR, as well as one that can toss a bayonet on.
Last gun was a KE Arms polymer lower, which I made a lightweight setup. Might not be WWSD light, but under 7 pounds. Lightweight barrel, carbine length D/I. Piston would have definitely boosted the weight up past 7 pounds, easily.
indianalex01
10-02-21, 22:43
I have pistons 516’s and MCX and Colt piston rifle. I also have many Colts 6920’s ect. I also have an SOT license so I shoot them all full auto and suppressed. DI on full auto is even better I feel due to a little less recoil (on full auto that matters). Suppressed then piston is better due to gas blowback. I have all sizes in both types. I enjoy both but I would take a DI gun (Colt 6933-EPR) 1st. DI guns aren’t front heavy either like a piston gun. I love the easy clean up of. Piston gun.
I have pistons 516’s and MCX and Colt piston rifle. I also have many Colts 6920’s ect. I also have an SOT license so I shoot them all full auto and suppressed. DI on full auto is even better I feel due to a little less recoil (on full auto that matters). Suppressed then piston is better due to gas blowback. I have all sizes in both types. I enjoy both but I would take a DI gun (Colt 6933-EPR) 1st. DI guns aren’t front heavy either like a piston gun. I love the easy clean up of. Piston gun.
Do you like the 516?
Not a study, but straight from the mouth of Karl Lewis when asked what advantage his piston guns had over his DI guns.
"Well, the pistons are more expensive to build. I make a little more profit on them."
So there's that.
Kind of like when I asked John Noveske if people needed to break in his barrels. We were talking over a bunch of things, and his reply was no. I asked him why other companies recommended special paste and swap methods for max accuracy. His rep,y was that each time people were swiping with paste or brushes, they were taking a little bit of life out of the barrel. He laughed and said if someone lost 30% of the max accuracy over the life of the barrel, he would make more money. However, he refused to ever tell people to do it.
Same could be said of any proprietary system or part. Keep a spare and you’re good to go.
I like my SCAR, but shoot my DI’s much more.
Buy, own and use what you like and has worked for you and what you do.
The only validation you need is your own.
Mysteryman
10-03-21, 14:38
If you run suppressed there is definitely a case to be made that they run cleaner than a DI gun. Also less gas to the face. I wanted a PWS in the worst way until I picked one up and the added weight was noticeable. It's hard to argue with the design. A couple billion AKs are still out there running strong.
If you run a flow through can it doesn't matter.
indianalex01
10-03-21, 15:45
Do you like the 516?
I love the 516. You can pic up 516 uppers on GB for great prices. Piston guns are pretty cool. Something different. I love all guns.
I love the 516. You can pic up 516 uppers on GB for great prices. Piston guns are pretty cool. Something different. I love all guns.
Let me join the choir here. I own several 516's. I think they are great rifles. Very well made. 100% reliable. Accurate. Only real drawback is weight. Like the 416, they are grossly overbuilt but that contributes to their reliability. Sig still makes them for military/LE use, but the MCX is now Sig's main AR style rifle.
indianalex01
10-03-21, 18:42
Kind of like when I asked John Noveske if people needed to break in his barrels. We were talking over a bunch of things, and his reply was no. I asked him why other companies recommended special paste and swap methods for max accuracy. His rep,y was that each time people were swiping with paste or brushes, they were taking a little bit of life out of the barrel. He laughed and said if someone lost 30% of the max accuracy over the life of the barrel, he would make more money. However, he refused to ever tell people to do it.
So true. Barrel break-in is BS. Gale McMillan also says this. Barrels can’t shoot themselves accurate. It’s gotten so stupid that I have seen people talking about breaking in a chromelined AR barrel and even Glock barrels. The stupidity
Let me join the choir here. I own several 516's. I think they are great rifles. Very well made. 100% reliable. Accurate. Only real drawback is weight. Like the 416, they are grossly overbuilt but that contributes to their reliability. Sig still makes them for military/LE use, but the MCX is now Sig's main AR style rifle.I have agree, my 2 Sig 516s have been 100% reliable for me. Heavy, but utterly reliable. I shoot mostly suppressed, so the ability to regulate gas is great. YMMV.
Sent from my SM-G960U using Tapatalk
If you run a flow through can it doesn't matter.
True, and I really like what OSS is doing with theirs, but I would hazard that the vast majority of cans out there are not using a flow through design.
Okay, "piston drive" covers a lot of ground. You have completely re-designed systems like the H&K et al., you have the retrofit systems, and you have the not AR based piston designs AR-180 etc. Making a general call "piston vs DI" which is better is impossible. As to a report or anything like that, who is going to gather all possible iterations of piston designs and score them?
We can find unbiased comparisons between individual weapons, like the M16A1 vs the Stoner 63, but they are few and far between.
There is the 2015 Re-Baseline Reliability Test of 5.56mm Weapons using M855A1 Ammunition though, reliability study of the M4/M16, the M27 and M249. Although, the object of the test is not to say "which is better", but to give quantitative data on how reliable each is.
So what were the numbers?
Out of 18 M4A1s, each shooting 6,000 rounds, there were 21 Class III failures and 413 Class I/II stoppages (232 of these were failure to lock back on the last round)
Out of 6 M16A3s, each shooting 6,000 rounds, there was 0 Class III failures and 9 Class I/II stoppages.
Out of 10 M27s, each shooting 4,800 rounds, there was 1 Class III failure and 24 Class I/II stoppages.
Class I - Operator correctable in less than 10 seconds or less
Class II - Operator correctable in more than 10 seconds (with use of BII tools if required)
Class III - Non-Operator correctable, ie, requires tools not available to operator.
turnburglar
10-05-21, 00:20
Wow Lysander that's actually really useful data points.
Thanks for sharing.
I really want to know how a 14.5 MID or a 16 MID/INT would fair in a test like that.
Based on how I am interpreting the data the M27 actually is far more reliable than the M4A1. Even if you go ahead and throw out all the failure to lock bolt back, the M4a1 is still massively skewed compared to the other two guns. What still surprising is that the original Rifle gas on a 20" barrel is the ultimate winner. Guess Stoner knew a thing or two about gasing and timing a gun??
Wow Lysander that's actually really useful data points.
Thanks for sharing.
I really want to know how a 14.5 MID or a 16 MID/INT would fair in a test like that.
Based on how I am interpreting the data the M27 actually is far more reliable than the M4A1. Even if you go ahead and throw out all the failure to lock bolt back, the M4a1 is still massively skewed compared to the other two guns. What still surprising is that the original Rifle gas on a 20" barrel is the ultimate winner. Guess Stoner knew a thing or two about gasing and timing a gun??
And, a lot of people jumped to that very conclusion. But, can you really say that?
There were almost twice as many M4 shooting, and they all shot 1,200 rounds more than the M27 (108,000 rounds for the M4s but only 48,000 for the M27). And, where do you expect to see more malfunctions? With a new gun, or one with a few thousand rounds through it?
The devil is in the details, as they say.
The report actually gives what all the stoppages and malfunctions were, and when they happened, as well as a lot of other pertinent information a little snippet like that post cannot hope to give.
And, a lot of people jumped to that very conclusion. But, can you really say that?
There were almost twice as many M4 shooting, and they all shot 1,200 rounds more than the M27 (108,000 rounds for the M4s but only 48,000 for the M27). And, where do you expect to see more malfunctions? With a new gun, or one with a few thousand rounds through it?
The devil is in the details, as they say.
The report actually gives what all the stoppages and malfunctions were, and when they happened, as well as a lot of other pertinent information a little snippet like that post cannot hope to give.
Don't know the details of the study but I'm gonna guess they didn't just grab a bunch of M4A1's off of arms room shelves from an infantry unit. Could be wrong, but I'd guess maybe they were new production guns?
I'd really like to know that answer if someone "in the know" could espouse on it. That would be a bit off the fairness track don't you think? If you're gonna try and prove a point then do it honestly (not you lysander, but the ones conducting the tests).
I did note the round count differences and less M27's were used. The sheer number of Class I, II, and III failures is kind of lopsided though. Even if you discount the failures-to-lock-back on an empty mag it is still lopsided to me. In a life-or-death firefight, not locking back won't matter unless it indicates a progressing problem.
BoringGuy45
10-05-21, 18:32
DI and piston guns have their pros and cons. I tried to take a balanced view, as I think there's a lot of "purism" by AR enthusiasts. The second someone suggests that there's merit to a piston AR, a bunch of guys start seeing red and get ready to launch a tirade against anyone who would suggest that a piston is anything more than a hairbrained solution in search of a problem. The fact is, both have their pros and cons. DI tends to be lighter due to less parts, it recoils smoother, parts are not proprietary, and the fact is, the AR was designed as a DI gun, so it just functions more fluidly in its natural configuration. But, it does run dirtier and hotter, it blows more gas back at the user, especially suppressed, and it gets finicky in short barrels. Pistons run cleaner and cooler and are easier to clean. But, they're heavier, they're proprietary, more expensive, and they have sharper recoil.
I guess the answer is...pick your poison. A good piston gun may be more reliable than a DI gun. I know that on paper the 416 time and time again has shown to have a smaller amount of stoppages on average than the M4, but is that mostly on paper, or is the difference in reliability enough to make a difference in combat?
Don't know the details of the study but I'm gonna guess they didn't just grab a bunch of M4A1's off of arms room shelves from an infantry unit. Could be wrong, but I'd guess maybe they were new production guns?
I'd really like to know that answer if someone "in the know" could espouse on it. That would be a bit off the fairness track don't you think? If you're gonna try and prove a point then do it honestly (not you lysander, but the ones conducting the tests).
I did note the round count differences and less M27's were used. The sheer number of Class I, II, and III failures is kind of lopsided though. Even if you discount the failures-to-lock-back on an empty mag it is still lopsided to me. In a life-or-death firefight, not locking back won't matter unless it indicates a progressing problem.
The reason there are so many M4s in comparison to all the others is there were several "types" of M4s
6 brand new ones
6 depot reworks
6 PIP reworks (MWO 9-1005-319-20-1, mainly the heavy barrel)
Now, I have actually provided this information in a spotty manner, to purposely lead you in a particular direction. I do this to show that even with a totally impartial report that has no intention of answering the question "who's better?" the person reporting the information to you can guide you to a predetermined conclusion. So when reading articles that draw conclusions from what should be impartial report, beware. I noticed this a lot when this test was first reported on and people wanted to say the M4 was a piece of poo compared the the H&K. In these Army reports, unless the title says "comparison", or words to that effect, and an article written about it draws a comparative conclusion, you can bet the author has a preferred direction he/she wants to lead you. (This applies to all reports on military equipment, from the F-35 to the M855A1 cartridge, BTW.)
THE REST OF THE STORY:
Of those 413 Class I/II stoppages, 353, and 7 of the Class III malfunctions in the M4A1 fleet were charged to the magazine, the M27 had no Class I/II stoppages or Class III malfunctions charged to the magazine (I believe they were PMAGS, but don't quote me on that). This shows that the M4A1 had a serious compatibility problem with its magazine (tan follower).
Now, if I said 108,000 rounds with 60 Class I/II stoppages, and 10 Class III malfunctions versus 48,000 rounds with 24 Class I/II stoppages, you might get the idea that the two weapons systems were on more equal footing. On the other hand, the magazine is part of the weapons system, so it really fair to throw out that data, just because it makes you look bad?
Somewhere in the 800 pages of this report there is a section on the Enhanced Performance Magazine (EPM) test, I am not in the mood to try and find it right now. I am pretty sure it shows some improvement.
Hammer_Man
10-06-21, 11:53
Lysander I just wanted to say thank you for providing some context.
The reason there are so many M4s in comparison to all the others is there were several "types" of M4s
6 brand new ones
6 depot reworks
6 PIP reworks (MWO 9-1005-319-20-1, mainly the heavy barrel)
Now, I have actually provided this information in a spotty manner, to purposely lead you in a particular direction. I do this to show that even with a totally impartial report that has no intention of answering the question "who's better?" the person reporting the information to you can guide you to a predetermined conclusion. So when reading articles that draw conclusions from what should be impartial report, beware. I noticed this a lot when this test was first reported on and people wanted to say the M4 was a piece of poo compared the the H&K. In these Army reports, unless the title says "comparison", or words to that effect, and an article written about it draws a comparative conclusion, you can bet the author has a preferred direction he/she wants to lead you. (This applies to all reports on military equipment, from the F-35 to the M855A1 cartridge, BTW.)
THE REST OF THE STORY:
Of those 413 Class I/II stoppages, 353, and 7 of the Class III malfunctions in the M4A1 fleet were charged to the magazine, the M27 had no Class I/II stoppages or Class III malfunctions charged to the magazine (I believe they were PMAGS, but don't quote me on that). This shows that the M4A1 had a serious compatibility problem with its magazine (tan follower).
Now, if I said 108,000 rounds with 60 Class I/II stoppages, and 10 Class III malfunctions versus 48,000 rounds with 24 Class I/II stoppages, you might get the idea that the two weapons systems were on more equal footing. On the other hand, the magazine is part of the weapons system, so it really fair to throw out that data, just because it makes you look bad?
Somewhere in the 800 pages of this report there is a section on the Enhanced Performance Magazine (EPM) test, I am not in the mood to try and find it right now. I am pretty sure it shows some improvement.
Not sure which tests you are referencing or the timeframe but PMAGS didn’t work in the 416 until Gen3 as I recall.
A true test should have included the HK magazines provided with the rifles, regardless.
Not sure which tests you are referencing or the timeframe but PMAGS didn’t work in the 416 until Gen3 as I recall.
A true test should have included the HK magazines provided with the rifles, regardless.
The test was 2015, like I said, "don't quote me on the PMAG."
turnburglar
10-07-21, 03:33
Thanks for clarifying that 12 out of 18 M4's where not brand new guns. Without all of the data it is very hard to draw a proper conclusion. If the HK guns where brand new AND using different magazines from the other guns that also ANOTHER variable to consider. Im sure magpul would tell you those M4 stoppages would clear up with the G3 Mags.
Yeah re-run that test using the EPM or the Magpul Gen3's and see what the results would be. M855A1 requires those mags for optimal long term functioning.
Thanks for clarifying that 12 out of 18 M4's were not brand new guns. Without all of the data it is very hard to draw a proper conclusion. If the HK guns where brand new AND using different magazines from the other guns that also ANOTHER variable to consider. Im sure magpul would tell you those M4 stoppages would clear up with the G3 Mags.
Shouldn't arsenal re-builds be "just about" like new? I mean everything is spec'd out in the process.
Shouldn't arsenal re-builds be "just about" like new? I mean everything is spec'd out in the process.
No. Rifles in service are allowed greater tolerances that new rifles. Keep in mind that they likely don't replace anything on a rifle in service until there's a failure, like bullets striking the target sideways.
Arsenal rebuilds often means the rifle passed inspection after being reassembled from the pile of parts from the two dozen they tore down.
No. Rifles in service are allowed greater tolerances that new rifles. Keep in mind that they likely don't replace anything on a rifle in service until there's a failure, like bullets striking the target sideways.
Arsenal rebuilds often means the rifle passed inspection after being reassembled from the pile of parts from the two dozen they tore down.
You might think that . . . but, the new builds account for 64% of the Class III malfunctions, while the rebuilds account for 99% of the Class I/II stoppages.
Here are the results from the EPM (blue follower) tests, 9 M4A1s, 3 new, 3 PIP, and 3 rebuilds, and 6 M27s, all shooting 6,000 rounds each:
New - 6 Class I/II, 3 Class III
PIP - 15 Class I/II, 4 Class III*
Rebuilds - 2 Class I/II, 4 Class III
M27 (M855A1) - 14 Class I/II, 0 Class III**
M27 (M318) - 2 Class I/II, 1 Class III
The initial MR firing dispersion of the new and rebuilt weapons was pretty much the same: New - 3.1", Rebuilt - 3.6"
______
* 10 of the Class I/IIs are from a single weapon
** evenly spread across all three weapons
The test was 2015, like I said, "don't quote me on the PMAG."
Wasn’t trying to give you a hard time and yes you did qualify that one. :)
One last thing on this subject.
"Are piston AR more reliable than DI* ARs?"
This is an impossible question to answer because there are many things that effect the reliability of a weapon. Look at the AR-18, the L85, and the G36, all basically the same operating system, but very different levels of reliability.
Even if you narrow the scope down to "Are piston retro-fit kits more reliable than DI ARs?" the variations on the theme are too varied to give a "yes" or "no" answer. So, the simple answer to the OP is "no". There are a good number of modified AR designs that are very reliable, the H&K MR556, Haenel's was supposed to be pretty good, as was the SIG 516. There are even a few retro-fit kits that work as well as the M4.
The comparison has to be individual, is a Ruger SR556 as good as an AR? Probably not, or they wouldn't have discontinued it. Is the H&K MR556as good as an AR?" Yes, and maybe a little better it certain cases. Is an Adams Arms carbine piston retro-fit kit as good as the M4 it was converted from? Probably, if you give it a heavier buffer (H2 or H3).
______________________________
* Yes, I know that the AR design isn't really a DI, as it has a piston in it, but you knew what I was talking about, so let's keep it simple.
^ I think that's a fair assessment.
On DI AR's not being a true DI, is that due to the bolt in side the carrier is
considered as the piston?
______________________________
* Yes, I know that the AR design isn't really a DI, as it has a piston in it, but you knew what I was talking about, so let's keep it simple.[/QUOTE]
On DI AR's not being a true DI, is that due to the bolt in side the carrier is
considered as the piston? I heard that said, just never knew exactly why, it's not a actual DI.
______________________________
* Yes, I know that the AR design isn't really a DI, as it has a piston in it, but you knew what I was talking about, so let's keep it simple.[/QUOTE]
On DI AR's not being a true DI, is that due to the bolt in side the carrier is
considered as the piston? I heard that said, just never knew exactly why, it's not a actual DI.
______________________________
* Yes, I know that the AR design isn't really a DI, as it has a piston in it, but you knew what I was talking about, so let's keep it simple.
IIRC the AR setup is called an "internal piston" or something to that effect. It is more commonly referred to as "DI" though. A true DI is like the French MAS49/56, which actually blows gas back via a gas tube into the brick-like carrier.....but it is a "blind" hole, i.e. it doesn't lead down into the bolt area, just blasts the carrier backwards.
IIRC the AR setup is called an "internal piston" or something to that effect. It is more commonly referred to as "DI" though. A true DI is like the French MAS49/56, which actually blows gas back via a gas tube into the brick-like carrier.....but it is a "blind" hole, i.e. it doesn't lead down into the bolt area, just blasts the carrier backwards.
Thanks, I appreciate it.
On DI AR's not being a true DI, is that due to the bolt in side the carrier is
considered as the piston? I heard that said, just never knew exactly why, it's not a actual DI.
______________________________
* Yes, I know that the AR design isn't really a DI, as it has a piston in it, but you knew what I was talking about, so let's keep it simple.
A DI system has a nub with a cup the gas tube fits inside of, or a nub the gas tube fits over and the gas directly drives the nub.
Gas in the AR flows into an expansion chamber and pushes the carrier to the rear, unlocking the bolt and extracting the spent case. Colt calls this system "direct gas". Eugene Stoner states in his patentn his patent, the gas system used in the AR is not a direct impingement system.
All gas systems use a piston, whether it's blow back, delayed blowback, direct gas, direct impingement or conventional gas piston.
Thanks, for the info. On the difference.
From U.S. Patent 2,951,424 - "Gas Operated Bolt and Carrier System, E.M. Stoner, patented Sept 6, 1960:
It is a principal object of this invention to utilize the basic parts of an automatic rifle mechanism such as the bolt and bolt carrier to perform a double function. This double function consists of the bolt's primary function to lock the breach against the pressure of firing, and secondarily, to act as a stationary piston to actuate the automatic rifle mechanism. The primary function of the bolt carrier is to lock and unlock the bolt by rotating it and to carry it back and forth in the receiver. The secondary function of the bolt carrier is to act as a movable cylinder to actuate the automatic rifle mechanism. By having the bolt carrier act as a movable cylinder and the bolt act as a stationary piston, the need for a conventional gas cylinder, piston and actuating rod assembly is eliminated.
It is an object of this invention to provide a gas system which is lighter and less expensive to produce because of its simplicity than the present gas systems now used in automatic rifle mechanisms.
It is another object of this invention to utilize the energy of the expanding gas developed by the firing of the weapon, for actuating the automatic rifle mechanism directly by use of a metered amount of the gas coming from the barrel. This invention is a true expanding gas system instead of the conventional impinging gas system. By utilization of a metered amount of gas from the barrel, the automatic rifle mechanism is less sensitive to different firing pressures caused by variations in the propelling charge. It is therefore still another object of this invention, to provide a rifle mechanism which is not affected by variations in the propelling charge.
Interestingly enough, Stoner specifically states his system IS NOT a direct impingement system.
https://i.imgur.com/rLBgS2I.png
... Stoner specifically states his system IS NOT a direct impingement system.
heads will explode. :cool:
https://i.imgur.com/rLBgS2I.png
Yeah top right graphic is what the MAS49/56 basically is.
I just have to add that the frog rifle is pretty simple to clean: Barrel, face of bolt, and hole in the carrier where gas tube dumps
Yeah top right graphic is what the MAS49/56 basically is.
I just have to add that the frog rifle is pretty simple to clean: Barrel, face of bolt, and hole in the carrier where gas tube dumps
It shows up a number of places:
https://gunblast.com/images/Ruger_RanchRifle/1Mvc-002f.jpg
https://cdn.shopify.com/s/files/1/0187/4100/products/WWII_German_G43_K43_Gas_System_1024x1024.jpg?v=1571438564
indianalex01
10-10-21, 22:57
The AR15 or M-16 gas system will always be considered direct gas. That’s not going to change. Technically you are right though.
Leonidas24
10-10-21, 23:18
The AR15 or M-16 gas system will always be considered direct gas. That’s not going to change. Technically you are right though.
I feel like that argument is equivalent to saying a toilet is a chair, therefor a chair is a toilet.
So are we all going to start using the term "expanding gas system or EGS" instead of DI to describe our AR's? Seems we should to be correct, at least technically.
This is just another piece of terminology used on the AR system that is used incorrectly.
Dwell time - Everywhere except the AR world, dwell time is the time from primer ignition to bolt unlocking.
Direct impingement - Every where else this is an expanding gas system.
There will probably be more in the future.
You might think that . . . but, the new builds account for 64% of the Class III malfunctions, while the rebuilds account for 99% of the Class I/II stoppages.
Here are the results from the EPM (blue follower) tests, 9 M4A1s, 3 new, 3 PIP, and 3 rebuilds, and 6 M27s, all shooting 6,000 rounds each:
New - 6 Class I/II, 3 Class III
PIP - 15 Class I/II, 4 Class III*
Rebuilds - 2 Class I/II, 4 Class III
M27 (M855A1) - 14 Class I/II, 0 Class III**
M27 (M318) - 2 Class I/II, 1 Class III
The initial MR firing dispersion of the new and rebuilt weapons was pretty much the same: New - 3.1", Rebuilt - 3.6"
______
* 10 of the Class I/IIs are from a single weapon
** evenly spread across all three weapons
Are we to assume that the M27 tally are "new" weapons? The original test stats outlined in your first post seems to be skewed all the way around with different condition M4 types versus presumably "new" M27 types. Add different round counts (original test) to the equation and it seems to me with a cursory review that the test is favored to the M27.
The same holds true with the "blue follower" test save for the constant round count, as rifle condition comes into play.
From my experience, and to obtain accurate results, controls should be in place i.e. both round count and rifle condition.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.